Physiologic correlates of the ERG hyperventilatory response in dogs.

Previous studies in man have shown that hyperventilation consistently enhances the amplitude of the electroretinogram (ERG) b-wave, but has little effect on the a-wave. The present study examined this phenomenon in the dog; central (centrifugal) and peripheral (sympathetic) neural effects and changes in arterial pO2 and blood pH were excluded as physiologic bases for the phenomenon. It was concluded, therefore, that the underlying mechanism must be decreased pCO2 (hypocapnia), although the specific site of action and the method by which the ERG b-wave is enhanced remain topics for future research.